Heater strips for such applications as heat tracing pipes and vessels are well known. For example, U.S. Pat. No. 3,793,716 describes a heater strip comprising two conductive wires embedded in a positive temperature coefficient polymeric material. U.S. Pat. Application Ser. No. 938,591 filed on Aug. 31, 1978, which is incorporated herein by reference, describes a pipe line heating apparatus comprising three flat resistive elements or conductors that run in spaced apart parallel relation along the surface to be heated. These three conductors are surrounded by insulation and sandwiched between two flat strips of aluminum. This heater can be strapped to a pipeline in substantial conformity with the shape of the circumference and length of the pipeline. The flat aluminum strips serve to conduct and diffuse the heat generated by the three flat conductors over the surface of the pipeline.
Heaters are spliced together by electrically connecting each of the three conductors of each heater to a corresponding conductor of another heater. In addition, heaters such as those described in Application Ser. No. 938,591 can be electrically terminated by splicing the three conductors of one heater together. Heaters are also connected to a power source via their conductors.
Connecting apparatus are needed for effecting these connections. It is desirable that one type of apparatus be used for all types of connections, and the apparatus can be used for conductors of different sizes. It is also desirable that the apparatus provide a moisture-proof environment for the connection so that the heater can be used in areas where water vapor is present. The apparatus should provide a connection that remains unaffected by chemicals likely to be found in and around pipe lines and temperature cycling. In addition, the apparatus should be easy to use and inexpensive to manufacture.